Python - Reversed Split Strings

In Python, there are times where we need to split a given string into individual words and reverse the order of these words while preserving the order of characters within each word.
For example, given the input string "learn python with gfg", the desired output would be "gfg with python learn". Let's explore a few ways to achieve this efficiently in Python.

Using split() and reverse

This method involves breaking the string into a list of words using the split() function and then reversing the list in place using the reverse() method.

s = "learn python with gfg"
# Break the string into words and reverse the list
words = s.split()  # Split into words
words.reverse()  # Reverse the list in place
print(words) 

['gfg', 'with', 'python', 'learn']

Explanation:

• The split() function divides the string into a list of words based on spaces.
• The reverse() method changes the order of the elements in the list to reverse.

Let's explore some more methods and see how we can split a string into a list of words and then reverse the order.

Using split() with slicing

This approach uses slicing to reverse the list after breaking the string into words.

s = "learn python with gfg"
# Break the string into words and reverse the list using slicing
words = s.split()[::-1]  # Reverse the list using slicing
print(words) 

['gfg', 'with', 'python', 'learn']

Explanation:

• split() function divides the string into words.
• Slicing with [::-1] creates a new list with elements in reverse order.

Using for loop

This method manually iterates over the string using a for loop, breaks it into words, and constructs the reversed list.

s = "learn python with gfg"
# Initialize an empty list for reversed words
words = []
# Break the string into words and iterate in reverse order
for word in s.split()[::-1]:
    words.append(word)  # Append each word to the list
print(words)  

['gfg', 'with', 'python', 'learn']

Explanation:

• split() function divides the string into words.
• The list is reversed using slicing, and words are added to a new list using a for loop.

Using list comprehension

This approach combines breaking, reversing, and collecting words in a list using a concise one-liner list comprehension.

s = "learn python with gfg"
# Reverse the list using list comprehension
words = [word for word in s.split()[::-1]]
print(words)  

['gfg', 'with', 'python', 'learn']

Explanation:

• split() function divides the string into words.
• Reversing is done using slicing with [::-1], and words are added to a new list with list comprehension.

Using reversed()

This method simply uses the reversed() function to reverse the list of words.

s = "learn python with gfg"
# Break the string into words and reverse using reversed
words = list(reversed(s.split()))  # Convert the reversed iterator to a list
print(words) 

['gfg', 'with', 'python', 'learn']

Explanation:

• split() function creates a list of words.
• reversed() function creates a reversed iterator which is converted to a list.